The present invention relates to a control device for adjustable chairs and the like. More particularly, the invention relates to a control device that makes it possible to adjust the reaction force of the backrest when the user leans against it, the position of the backrest, the tilt of the backrest with respect to the seat surface, and adjusting the gas lever that adjusts the tensions of the backrest.
As is known, office chairs, for example, are provided with adjustment devices, both for the tilt of the backrest and for the reaction force which the backrest can exert when the user leans against it, adjusting the gas-operated activation lever of the backrest tension.
The devices of the known type are typically rather complicated in terms of the number of components and therefore susceptible to breaking down and also involve maintenance issues in that repairs are costly and complicated.
In particular, generally, the adjustment mechanisms for backrest tilt with respect to the seat have a rear support which revolves on the shaft fastened to the support base. Normally, a blocking head is fastened to the rear support by welding or other mounting systems. This blocking head has a plurality of openings and a movable insert and has the possibility of sliding on the appropriate track and has the function of engaging, or not engaging, the openings. If the insert is positioned within an opening, the mechanism is in the blocked position. If the insert is positioned outside of the openings, the mechanism is in the released position. Such a blocking system is typically operated by rotating a lever.
As stated above, the movement of the insert that makes it possible to engage in the openings is produced, in devices of the known type, using a number of components making the mechanism complicated, and this situation is also reflected in the adjustment of the tension of the backrest, that is its reaction to the weight of the user who rests against it.